Tunnel kiln



Jan. 8, l1929. 1,698,700 I G. W. BOOTH r TUNNEL KILN Filed March 28,1927 2 Sheets-Sheet 1 lxlln LD tj! f1 Si m1500270 -il MMUnHUu J l@ /T||w|1i|mwr|n IHM IHN --1 1---. -m VMM IMUHHWIIIH wl .M HH HH .MH ml@ -il.. Huw JIM .,Hl hill MII... ....IIVMILIILII-. Tl l1 1| Ln- ----l ---1-JEL. --J\ Mm,

G W. BQQTH TUNNEL KILN Jan. 8, 1929.-

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YuNrrEo s'rAlrEs PATENT A OFFICE.

GEORGE w.y BOOTH, or NEW TORONTO, ONTARIO, OANADA.

TUNNEL KILN.

lAvmilication led March 28, 1927. Serial No. 179,074.

This invention relates to tunnel kilns for clay products of the typeshown and described in my prior United States Patent 1,585,013, datedthe 18th day of May; 1925, in which the drying ofthe ware is eifected ina chamberor f chambers extending lengthwise of the kiln. y

By such an arrangement a considerable saving vof otherwise waste heat iseffected.

at the top 'My present object is to devise an improved constructionwhereby still greater economies may be effected and whereby more perfectcontrol may be had of the successive operations of drying, pre-heating,ringandcooling.

' as described, or shifted in the tunnel towards or away from thecooling or the pre-heating zone. A further important feature is thearrangement whereby perfect control of the drying air at different partsof the length of thedrying chamber is obtained-and the moisture contentof the ware thereby abstracted at suchva rate that warping and checkingof the Ware is avoided. Further novel features of the construction arehereinafter described and illustrated in the accompanying drawings inwhich Fig. 1 is a plan of a kiln constructed in accordance with myinvention;

Fig. 2 a side elevation of the same;

Fig. 3 a vertical section on the line 3--3 vin Fig. 1;

Fig 4 a longitudinal section on the line 1 4 .in Fig. l;

Fig; 5 a horizontal section of the kiln; and

Figs. 6 to 14 are transverse sections on the lines 6 6, 7 7, 8 8, 9 9,1o 1o, n n, 12-12, 13-13 and 14-14 in Fig. 5.

In the drawings like numerals of reference indica-te corresponding partsin thedifferent figures.

1 is the tunnel of the kiln which, as usual7 comprises pre-heating,firing and cooling Zones. Thepre-heating zone extends from A to P (seeFig, 5), the firing zone from B to C. and the cooling zone from C to D.On top of the tunnelof the kiln is arranged the drying v.chamber 2extending substantially from end to endyofthe tunnel. Both the tunnel 1and the drying chamber 2 will be arranged as usual for the passage oftrucks carrying the ware to, be tired.

In the drawings I have shown two dryingv chambers side by side, as thismakes va convenient arrangement.V It will be understood .of course, thatone only may be employed without departing from the spirit of myinvention. l

Air heating and drying system.

of the kiln is formed an air supply conduit 3 to whichair may besupplied by means of a fanfl. This conduit` extends transversely of thekiln and communicates at opposite ends l 7o Adjacent the outer end ofthe cooling zone,

with air passages 5 formed in the vwall of the kiln at each side of thecoolingzone. These passages extend from one end to the other of thecooling zone whereby there is a transfer of heat from the interior ofthe cool- Extending under the bottom of the kilnl Ving zone to the, airin the passages 5. To faare one or more longitudinal air passages 8, I

which extend past the firing `zone of the kiln andcommunicate with `atransverse air supply conduit 9 connected with the discharge outlet of apressure fan 9a. The passages 8 communicate with a pluralityOf'vertical' flues 10 extendingup` at both sides ofthe inner'wall of thepre-heating zone of the kiln. These iiues are separated byv meansV oftheirvmetalwfalls 11 from the productsof combustion flues hereinafterreferred to.

Each flue 10 is provided with van .upper and lower Opening 12, whichopenings are formed in the inner wall of thepre-heating Zoneforadmitting air from the'flues 10 into the interior of the tunnel.Anydesired numberof these flues or openings may be closed mf y bysuitable plugs (not shown) at any time to meet the needs of the caseaccording to the qualities of the ware to be fired.

From the constructions described it follows that air under pressure maybe introduced into the cooling Zone, or the pre-heating zone, or'both,by either fan 4: or 91 so that the products of combustion in the firingZone may ybe held therein or allowed to travel somewhat towards eitherend of the kiln as maybe required.` It further follows that heatedv airis provided'to pre-heat the ware' passing throughthe pre-heating Zone ofthel kiln and to assist'in the oxidation of the ware therein.Hereinafter it will appear how the vhot products kof combustion areutilized to heat the walls of the pre-heating zone, and

also to assist in heating the air passing through the tlues 10.

The air which passes through the lues 8 under the tunnel serves to coolthe space bee nea-th the trucks passing through the Zones of the kiln.The air heated in the air passages extending along the sides of thecooling vzone of the kiln is utilized in drying thel ware passingthroughkthe gdryingchambers y by means of the following constructions.At

eachs'ide of the kiln the' air passage 5 communicates with a verticalpassage 13, which communicates at its lower end with one of the ai'rjpassages VS and, at its upper end, with a longitundinal air distributingpassage 14 which extends substantially from end to end iof the kiln.Damper's are provided atieachV end of each :vertical passage 13.V At'each side, above the corresponding air distributing passage 14, islocated an air passage 15 transversely divided into sections, eachsection communicating by means `of a damper controlled opening 16 withthe air distributing passage 14. l farm dry air may thus be in troducedinto each section according to cir-V cumstances. Each vsectioncommunicates with the interior of the adjacent drying chamber by meansof a longitudinal seriesl of openings 17 These openings,'it will benoted, are arranged along the top of the outer side wall of the dryingchamber; Ceni trally of the kiln at or'about the level vof the lowerpart-s of the drying chambers I pro vide moist air flues 18. -Vhile oneHue might serve jI prefer to employ two as conditions 'in the two dryingchambers may not be exact-ly the same. V'Ihe lower part of each dryingchamberv communicates with one of the moist air flues by means of alongitudinal se# ries of openings 19. The moist air tlues are preferablydivided into sections like `the air passages 15,V and each sectioncommunicates by means of a damper controlled opening v20 with the.draw-,off passage 21, which extends longitudinall of the kilnandadjacent the inlet end of t e drying chamber is provided with a suctionfan 22 whereby the moisture laden air may be drawn o.

From the constructions described it follows that perfect control may beobtained of the admission of drying airand the drawing-off of moist airat dilferent points along the length of the drying chambers so that therate of drying at dierent parts of the drying lchamber may be accuratelycontrolled to prevent warping and checking of the ware. While manuallycontrolled dampers might be employed, I prefer-toV employ automatic ltemperature and humidity controllers, such as are well knownV in theart, andv which are illustrated diagr-ammatically. in the drawings.

The #ring sli/stem 'and utilization of the 'waste heat 0f the productsof combustion.

While any Vfurnaces of known type may f be employed, I prefer to employthe furnaces illustrated, which are preferably of different types atdifferent point-s in the length of the firing zone to enablethe tiringto be carried as best suits the-requirementsof the ware to be fired.Four types of furnace are illustrated, which are bestseen in Figs. 9,10, 11 and 12 'of they drawings. Y. y

The first furnace I in the series illustrated Y in Fig. 12 is ofvordinary type, and is preferably provided with a draft damper 23 auto=matically controlled by an automatic temperature controller of knowntype. This fur- `nace communicates directly with the interior of thekiln through an opening 24. At each side of the tunnel I form a flue 25for thel products of combustion communicating with the interiorof-the'kiln lby means of openings 26.v The products of combustionentering the tunnel Athrough the openings 24; may thus be drawn offthrough the flues 25 afterv trayelling a greater or less distancethrough the tunnel and around the ware being fired. Preferably theseries of openings26 is extended substantiall'y the full llength ofthepre-heating and firing rones of the kiln, as

some wares are not injured by early contact f At this end the fluescommunicate with down'- i wardly extending and transverse iiues 29communicating with a transverse flue 30, with which communicates thesuction fan 31 by .means of `which the produ-cts of combustion may .bedrawn off. Under some conditions the `moist air from the draw-0Evpassage 21 may be allowed to pass ofi' with the products of combustion.I therefore provide each draw-cti passage with a damper controlledcommunication 32 with the transverse passage 27. 1t will be' noted thatthe hot products of combustion are utilized to heat the air passingthrough the flues l0, which air lissupplied through either thesairsupply conduit 3,'orthe air supply conduit'9, or both.4

The second furnace II communicates with the interior of the tunnelthrough the openings 33 over the Hue 25.

The furnace HI communicates with the interior of the kiln throughthe-openings 34k,u

passage 34a and openings 34h, while furnace numberIV communicates withthe interior of the tunnel through the openings 35. Any one or anycombination of the furnaces may be used as desired for different classesof ware.

With the furnaces arranged as described hotproducts of combustion may becirculated in any desired manner through the ware to be fired.

All the furnaces areipreferably provided with automatic dampercontrollers similar to that of furnace No.` l, and generally speakingany of the openings or passages of the kiln may be provided-withdampers, though not hereinbefore set forth. l Y

It is obvious that theV arrangement described not only gives me perfectvcontrol of the drying, pre-heating, firing, and cooling of the ware butresults in economy in operation as otherwise waste heat is utilized tothe greatest possible extent and perfect control the drying chamber atdierent points inits length; dampers controlling the communi-L cationsbetween the distributing passage and the sections of the sectionalpassage; and means for drawing air through the said passages, chamberand flue.

2. A kiln constructed as set toi-th Vin claim 1 in which the moist airflue is formed in separated sections and a` draw off passage. isprovided in communication with each sectionv by means of dampercontrolled openings. A 3. The combination of a tunnel kiln; a separatedrying chamber; an air passage formed in a wall of the chamber'communicating with the interior of the chamber at different points inits length; a sectional moist air fine' extending longitudinally of thekiln,

series of openings; a vdraw-off passage coin-- municating witheachsection of the moist air flue; dampers controlling thecommunications between the draw-oftz passage and thesections of themoist air flue; and means for drawing air through the said passages,chaniber and flue. l

4. The combination of a tunnel kiln; a sep`V arate drying chamber; adistributing air passageformed in the wall of the chamber extendinglongitudinally thereof; an air passage arranged adjacent thedistributing passage divided into sections, each section communicatingwith the distributing passage and with the interior of the dryingchamber; a sectional moist air flue extending longitudinally of thekiln, eachrsection communicating with the interior of the dryingchamber; a draw-olf passage communicating with 4each section of themoist airfiue; dampers controlling they communications between thedraw-off passage and lthe sections of the moist air fine; and means fordrawing air through the said passages, chamber and flue.

5. rlhe combination of a tunnel kiln; a separate drying chamber arrangedat the top of'` the kkiln whereby the chamberl will be heated byconduction from the kiln; an air passage formed longitudinally in a wallof the chamber and adjacent the kiln, the passage having a. series ofopeningscommunicating with the interior of the chamber; a moist air iueextending longitudinally of the kilnk communicating with the interior ofthe chamber at different points in its length means for drawing airthrough the said passage, `chamber Vand flue; a furnace; passagesfforthe products of combustion including a Hue in the'wall of the chamberparalleling the aforesaid air passage; and means for drawing theproducts of combustion through said passages and flue A from the kiln. sv.

` 6. ri'Che Vcoml'iination of a tunnel. kiln; a separate drying chamberarranged at they top ofthe kiln whereby the chamber will be heat-Y ed byconduction from the kiln; an air passage formed longitudinally in a wallof the chamber and adjacent the kiln; the passage having a seriesofopenings communicating with the interior of the chamber; a moist airflue extending longitudinally lof the kiln communicating withwtheinterior of t-he cham: ber at different points in its length; means fordrawing..airthrough the said passage, chamber and flue.; a furnace;passages forthe products of combustion including alflue in `the wall ofthe chamber parallelinff the aforesaid air passage; meansjffor drawingthe products of combustion through said passages and'flue from the kiln;and a damper products of combustion whereby the moist air may be carriedoli with the products. oi'

. combustion when desired.

7. A tunnel `kiln comprising a pre-heating, a liring and a cooling zone1n combination with :an air heating passageformed in the wall of thecooling zone of the furnace; an air supply conduit communicating withthe air heating passage and the interior of the cooling zone oi' thekiln; means for con-trolling the proportion of air passing to each; aV

drying chamber; and means for leadingthe heated air into said dryingchamber.'

8. A tunnel kiln comprising a pre-heating,

' heating passage and the interior of the cool- CAB ing zone of thekiln; .means for controlling the proportion of'airpassing to each; adryingl chamber; means yfor leading the heated air into saiddryingchamber; and a passage under the kiln communicating with the air conduitaforesaid -and with the interior of .the tunnel at the pre-heating zone.j

9. A tunnel kiln comprising a pre-heating, l

a tiring and a cooling zone in combination with an air heating passageformed Vin the wall of the cooling Zone of the furnace; an air supplyconduit communicating with the air heating` passage and the interior ofthe cooling zone of the kiln; means for controlling the proportion ofair passing to each.; a drying chamber; means for leading the heated airinto said drying chamber; a passage under the kiln communicating withthe air conduit aforesaid and with the interior of the tunnel at thepre-heating Zone; a flue through which the products of combustion fromthe firing zone are passed and which vextends along theY wall of thepre-heating zone; and means for effecting an exchange of heat betweenthe said liuc and the air from the last mentioned passage as it passesinto the pre-heating Zone of the kiln.

10. A tunnel kiln comprising a pre-heating; a firing and a cooling zonein combination with a passage extending throughout the greater part ofthe length or the three zones; an air supply conduit communieating withsaid passage and the interior of the cooling zone of the iurnace, thepassage also communicating with the interior of the pre-heating-Zone ofthe kiln; and an air supply conduit communicating with said passage adjacent the pre-heating zone end of the same.

11. A tunnel kiln comprising a pre-heating, a tiring and a cooling' zonein combination with an air vheating passage formed in the wall of thecooling Zone of the furnace; a drying chamber; an air distributingpassage communicating with the Vair heating passage adjacent the innerend of the cooling zone; means for leading air from the distributingpassage to and through the dryingy chamber; and an 'air supply conduitcommuV nicatmg with the air heatingpassage and the interior of thecooling zone ofthe kiln adja' cent its outlet end. j

12. A tunnel kiln comprising a pre-heating, a firing and a cooling zonein combination with a flue for the products of combustion extendingalong the wall of the pre-heating zone; a vertical flue extending up theside of and communicating with the pre-heating zone of the kiln andpassing through the products of combustion flue; and an air supplyconduit communicating with the Ver'ti` cal flue.

13. A tunnel kiln comprising a pre-heating, a tiring and a. cooling zonein combination with a flue for the products of combustion extendingalong the wall oi the pre-heatL ing Zone; Vert-ical flues extending upthe side ofand communicating with the bottom and' top of the pre-heatingZone of the kiln, the said flues having metal walls separating them fromthe products of combustion iiue; and an air supply conduitcommunica'tingwith the Vertical flues. j

' -14. Atunnel kiln comprisingapre-heating; a tiring and a cooling Zonein combination with a flue for the products of combustion located in thewall of the kilnand extending along both the liring and pre-heatingZones;

a furnace communicating with the interior of the tunnel at the firingzone adj acent theco'oling zone; openings' being formed from theinterior of the tunnel into the iuerat dilerent points vin the length oithe vfiring zone ;l means for drawing gases from said liuc; and meansfor introducing air under pressure into the interior of the tunnel atthe preeheating zone.

l5. A tunnel kiln comprising a pre-heating; a firing and a cooling zonein combination with aflue for the products of combustion` located in thewall of the kiln and extending along both the firing and preheatingzones; a furnace communicating with the interior of the tunnel adjacentthe cooling zone, openings being ormed from the interior of the tunnelinto the flue at different points in the length of the liring zone andthe pre-heating Zone; means for drawing gases from saidflue; and meansforfintroducing Vair under pressure into the interior of pre-heatingZone.

16. A tunnel kiln comprising a pre-heating; a iiring and a cooling Zonein combination with a flue for the products of combustion the tunnel atthe ucts of combustion from the drying chamber Hue; means forpre-heating air; a passage for air extending along the wall of thedrying chamber communicating with the interior of the chamber; a moistair Hue alsocommunicating with the interior of the chamber; means fordrawing air from the moist air Hue; and a damper controlledcommunication between the moist air Hue andthe drying chamber Hue forproducts of combustion.

17. A tunnel kiln comprising a pre-heating, a firing and a cooling zonein combination with an air passage along the bottom of the tunnelextending from the cooling zone to the pre-heating Zone Vandcommunicating with the interior of the tunnel at the pre-heating zoneand the cooling zone; an air supply con-V duit connected with thepassage; and means for controllingl the How therefrom to the said zones.Y

18. A tunnel kiln comprising a pre-heating, a firing and a cooling zonein combination with an air passage along the bottom of the tunnelextending from the cooling zone to the pre-heating zone andcommunicating with the interior of the tunnel both at the preheatingzone and-the cooling zone; air supply conduits connected with thepassage adjacent opposite ends and means for controlling the Howtherefrom to the said Zones.

19. A tunnel kiln comprising a pre-heating; a Hring and a cooling zonein combination with a vHue for the products of combustion located in thewall of the kiln and extending along both the firing and pre-heatingZones; a furnace communicating with the interior of the tunnel at thefiring zone adjacent the cooling zone, openings being formed from theinterior of the tunnel into the Hue at .different points in the lengthof the Hring zone; means for drawing gases from said Hue; and-means -forintroducing air under pressure into the Y interior of the tunnel at thecooling zone. Y

20. A tunnel kiln comprising a pre-heating, a Hring and a cooling Zonein combination with a `Hue for the products of combustion locatedin the.wall of the kiln andextending the pre-heating zone; and means fordrawing gases from said Hue at a point remote from the furnace.

21. A tunnel kiln comprisinga pre-heating, a. Hring and a cooling zonein combination with a Hue for thel products of combustion located in thewall of the kiln and extending along both the Hring andpre-heatingfzones;

a furnace communicating withthe interior of the tunnel adjacent thecooling zone, open ings being formed from the interior of the tunnelinto the Hue at diHerent points in the length of the firing zone and thepre-heating zone; means for drawing gases from said Hue; and means forintroducing air under pressure into the interior of the'tunnel at thepreheating Zone and atv the ycooling zone.

22. A tunnel kiln comprising a pre-heating, a firing and a cooling zonein combination with a passage extending throughout the greater' part ofthe length of the three zones and communicating with the interior ofboth the cooling and pre-heating Zones; means for supplying air underpressure to said passage; and means for controlling the air passing fromthe passage into said zones to vary the relative proportion of airHowing to each.

Signed at Toronto this 3rd day of March, 192 l lesoneri w. Boorii.

